“Green and Brown” Grazing Strategy

educe seed production, and control or prevent
annual grasses. Within the context of an EBIPM
program, managed grazing using the “Green
and Brown” strategy is primarily designed to
alter relative species performance, but
managers using grazing can also influence
species availability and even site availability in
creating different disturbances.
The Dynamics of Grass Growth and the Response to Grazing
Grazing is considered a natural process in
grasslands. As a result of the process of
grazing, livestock remove litter, recycle
nutrients, stimulate tillering of perennial plants,
and reduce seedbanks of competitive annual
plants.
There are two fundamental differences in life
strategies between annual versus perennial
grasses that allow land managers to exploit
them using grazing and these differences form
the basis for the “Green and Brown” strategy.
The first difference is annual grasses have a
growth period different than many native
perennial grasses and many non-native
The photo above was taken in eastern Oregon in mid-March
and illustrates the capacity of cheatgrass to germinate and
begin growth initiation earlier than perennials.
10 - The Dynamics of Grass Growth and the Response to Grazing
perennial grasses as well. Annual grasses such
as cheatgrass and medusahead germinate in
the late-fall, winter or early-spring. Germination
is prompted by precipitation occurring when
temperatures are high enough for biological
activity. Even when they germinate in the spring
it is usually very early, prior to the time when
most perennial grasses come out of winter
dormancy and begin to grow.
This difference makes invasive annual grasses
temporarily more preferred and selected by
livestock and sets up an opportunity to develop
a grazing strategy that exploits this difference.
It’s called “Green and Brown”. When invasive
grasses are green, it indicates they
are actively growing, very
palatable, highly nutritious, and will
be preferentially selected by
livestock. Grazing at this time
reduces the competitive ability and
seed production of annual grasses.
On the other hand, perennial
grasses senesced or not growing,
are of low nutritive value during
much of the period that annual
grasses are green and growing
(See “Green and Brown table on
pages 6-7). In addition, senesced
perennial grasses are very tolerant
to grazing when they are brown.